Self organising steel balls explain metal heat treatment

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Metals have a crystal structure. But they're not one big crystal, they're lots of small crystals called grains. The size of the grains affects the physical properties of the metal, like hardness, toughness, strength, mailability, ductility, plasticity. Heating a metal can change the size of the grains. This ball bearing model demonstrates annealing.
Ductility is dependent on how far dislocations are able to travel in the metal which is dictated by grain size.
Original ball bearings video here: • 3000 ball bearings sho...
Other metal heat treatment videos here:
• Heat Treatment -The Sc...
• Properties and Grain S...
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Image credits:
First microscope grain image (1:11):
Tugsataydin
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Second microscope grain image (1:19):
Edward Pleshakov
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Dislocation diagrams (4:14, 4:18):
Cdang
commons.wikimedia.org/wiki/Fi...
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[@RalphDratman]

This is the first time (in 69 years and now 70) that I have ever understood something intuitively in metallurgy! Most discussions of metallurgy concepts tend to give information of various effects, but no real explanation. Thank you so much.

[@TheRainHarvester]

Ralph, you may really like this video too: "Primordial Particle System - The Trailer".

[@Dev1nci]

Ralph Dratman I’m not surprised that for at least 5 of those 68 years you didn’t find metallurgy intuitive (not that most 6-year-olds grasp metallurgy either) 😅 😉

[@simpleriverlife78]

Dido YOUNG Man... Dido!

[@MarioGoatse]

Terry Hicks The word is actually "ditto", my friend.

[@VulcaNtGoF]

@@MarioGoatse Isn't Dido that singer that Eminem did the song with?

[@thewilltheway]

They need to show this in materials class. This is so accurate and intuitive.

[@trashdilan]

"we need to jiggle the balls."

[@1mikewalsh]

My metallurgy teacher had pictures for us.

[@R.Daneel]

Make the demo sheet flexible somehow, and it may visually demonstrate plasticity too. Not sure how I'd bend it on the same plane as the bearings, though, which would be the best demonstration.

[@locklear308]

That would require them to want to make students smart, unfortunately that's not the goal...

[@whereammy]

i'm sure the ball jiggling part would be popular

[@TalRohan]

This is by far the best explanation of mettalic plasticity that I have ever seen, very easy to understand and not bogged down by the other "side effects" because you avoid them in a careful and well thought out way. 10/10 Steve

[@singerofsongs468]

I’m a materials science major, and I always find myself coming back to this video and the last one to hear about crystal lattices and their properties. Everything is, to the best of my knowledge, quite precisely-worded and accurate without sacrificing the accessibility of the language or concepts. And those videos of the vibration causing the lattice to shift around? Phenomenal. What a beautiful visualization. Thanks for making this video! I owe the fact that I do what I’m doing right now partially to science communicators like you.

[@thepewplace1370]

I know there's a year gone by since your comment, but aVe has a great video describing the phase diagram of steels, what it equates to physically, and the molecular/grain structures corresponding. It is one of only 3 or 4 videos, this one included, that has been so intuitive to digest.

[@singerofsongs468]

@@thepewplace1370 Thanks for the recommendation! I’ll be sure to check it out.

[@jepoyburner]

As a materials science teacher. I'm impressed by the level of clarity and accuracy of this video. Would totally make something similar for my class.

[@TheRainHarvester]

Jeffrey, you can show your class this video that has slider bars to vary the velocity and heat, and radius. "Primordial Particle System - The Trailer"

[@S_Carol]

There's actually a cheap DIY method for this that just uses water, soap, a balloon, a glass capillary, and a shallow container.

[@weinerglory]

omg teachrt is holosimp

[@rusalkin]

and that while being high as fuck, respect

[@combatdigiq]

the day your teacher job gets nullified by a youtube video ...

[@tonysolar284]

1:51 My inner kid laughed a bit.

[@azz2]

Someone needs to take this out of context.

[@nonhuman1104]

I'm not the only one thank god now I gotta finish grading this bullcrap to get my majors

[@Jimmypl007]

Looked for this comment.

[@SteveFrenchWoodNStuff]

Everybody's inner child laughed about that.

[@henrysutulovich6608]

That feeling when something makes you giggle and you head to the comments to see if anyone else is as juvenile

[@stevesyncox9893]

As a self taught bladesmith, I really appreciate this kind of “hand on” demo. Thanks man.

[@griffin9649]

As a student studying material science and mechanical engineering, this has to be my favortie video to date! That dislocation at 2:29 was incredible! Thanks for the fascinating content steve!

[@geofisika8838]

Hell yeah colleague!

[@Mobius118]

Let’s goooo boys

[@polerin]

It reminded me of a flyer in the game of life. Very interesting how simple propagation rules result in such dybamic behavior

[@gcewing]

The important thing to take away from this video is that KZbinrs should always jiggle their balls at a multiple of their camera frame rate.

[@eisenwerks6388]

Instructions unclear, testicles on fire.

[@mailleweaver]

That's interesting. The liquid you poured from the beaker at the end turned into a gas after pouring and then quickly condensed back into a liquid again.

[@cedrick25]

woah, that's really interesting

[@samuelmatheson9655]

It's black magic

[@paulbfields8284]

When I served my Tool and Die apprenticeship, under my father, I learned about Space Lattice..Austenite and martensite. I have known and felt what you are demonstrating here for my entire 42 year career. I have heat treated, hardened, tempered, stress relieved and annealed and this is the first time I’ve seen what I know, demonstrated perfectly. Thank you so much. I’ve told my apprentices over the years that you have to think like a molecule in order to properly handle the machining of steels..

[@nr7000000001]

Yes funny that you can somehow feel what is happening.

[@mpetersen6]

Stress Relieving. We used to do mechanical stress relieving with a piece of equipment called Formula 62. Plus when teaching apprentices about machining I always found it helped to get out my metallurgy books and show them micro graphs of just how metals cut. They never cut at the tools edge. They tear in front of the tool.

[@PopeGoliath]

*sighs in relief* It's been too long since I had a good beaker pour.

[@sprinkhole58]

poor beakers...

[@madkirk7431]

Lmao

[@rschiwal]

"That's why dislocations are sometimes called 'the carrier of plasticity.'" I've ALWAYS wondered why that was.

[@JoseRojas-hl7sn]

Really really or faky faky?

[@UnknownVir]

Here I thought it was because you'll need plastic surgery after enough dislocations.

[@Raeilgunne]

also explains strain hardening. once the dislocations are all at grain edge, the piece can no longer plasticly deform, and can only snap.

[@HimanXK]

As a materials engineering student, it's cool to see matsci and metallurgy showing up more in edutainment spaces. Seems like it's becoming more popular overall

[@Rumbleghost]

Within it's limited scope, this is the best introductory (or refresher) explanation of metallurgy that I have ever come across. This will help grok metals, rather than just pass the exam.

[@SergeantSphynx]

Materials was my favorite subject during my engineering degree. I was one of the weird ones who really enjoyed learning about crystalline structures and defects, and how to achieve the material properties you want in an alloy. I just find the subject fascinating.

[@howardbaxter2514]

I also loved the class too. I thoroughly enjoyed the labs because we got to use different machines to determine the different characteristics of a metal (like hardness, tensile, and shear strengths), and we were able to use different treatment and quenching techniques to see how it impacted the characteristics of the metal, whether that be steel, aluminum, or cast iron. The only part I didn't really care for in the class was all the different units and measurements. It makes sense why there would be so many, but it was always hard to remember what each number and letter represented what when it came to units and measurements of a certain metal.

[@djfunk8000]

Hey Steve. I’m a metallurgist in the United States and I really appreciate the videos you’ve done on crystal structure and how it relates to metals and their properties. I may just share this vid with our team to help explain metallurgy to the non-metallurgists I work with. Thanks for sharing

[@nareik8017]

Does this video then also accurately explain why you can only bend a piece of metal so many times? Because the imperfections are no longer spread out enough through the metal, causing it to break instead?

[@KitChen5548]

@@nareik8017 problem is when you bend it back, the microsheets in the metal, and the grains push against each other and break

[@BlueFlash215]

​@@nareik8017 there is a lot lacking from this model. It is a nice way to show how crystals and imperfections form and why some of them don't seem to be bothered by low heat (or kinetic energy here).

[@callumhunt1348]

As steve explained, when you exhaust the plastic limitation, that is the glide of dislocations and point defects, you can initiate cracking, but a lot of metals are ductile at room temperature, meaning a crack wont necessarily cause complete failure, often a crack can be within a grain referred to as a microcrack, and you repeat the deformation process, you generate more microcracks which can accumulate and weaken the structure, eventually leading to complete failure. This also is a simplification and there are many mechanisms why cycling loading can cause failure.

[@Arashi_2358]

I see Hank Reardon's brilliance in a new light.

[@rennoc6478]

As a person whos interested in majoring in chemical, materials, or mechanical engineering i really love it when you cover materials science concepts

[@druba7128]

As an engineer, this is one of if not the best explanation of this concept I've seen. So intuitive I'm going to make this a program at the science museum I work part time at

[@AchiragChiragg]

I'm working on a research paper on heat treatment and this was a pleasant surprise to watch.

[@actually_well_]

good luck on your paper goku

[@drinkthekoolaidkids]

If you've done any research on Google concerning your paper then it's not such a surprise that this video is in your recommendations , yesterday I was having a phone conversation some one and mentioned about my experience working in a metallurgy research lab , and guess what this video comes up in my recommendation.

[@andymcl92]

@@drinkthekoolaidkids Careful of confirmation bias! Typing something in to Google then getting a suggestion, fair enough. But saying it aloud then getting a suggestion, I'm still not convinced. But if I read in to your comment that you hadn't come across Steve before, welcome :)

[@TheRainHarvester]

Achirag, I made a few videos where I vary more parameters like radius and velocity. Search "Primordial Particle System - The Trailer", there is another where I got heart beat behaviour!

[@AchiragChiragg]

@@TheRainHarvester I will check it out!

[@yevrahhipstar3902]

As a Metal fabricator/welder, I've sat through a lot of lessons on metallurgy. First time I've heard about dislocations and their implications. I'd like to thank you and your balls of steel, Mr Mould, for this moment of clarity.

[@auricstorm]

Did you enjoy watching him jiggle his balls as much as I did? Haha

[@rachelclifford9190]

Hi Steve! I'm a grad student studying the transition of Opal A from diatoms all the way to quartz in the earths crust, which is to say to transition from amorphous silica to crystalline quartz. This is such an incredible description of that process that I actually showed your video to my advisor who then showed his class! I use X-ray defractometry (XRD) to determine the spacing between atoms based on the angle at which they defract x rays in order to identify the minerals in my samples. Since you love resonance and crystallization, I thought a video in which you break down how we can use x-ray defraction to determine crystal structure sounded like your bread and butter!

[@autumn1546]

Oh my god, the first 2 seconds plus the title just explained the concept you're trying to communicate instantly, that's absolutely incredible

[@craigcorson3036]

Eons ago, when I was still a young man, I worked as a heat treater. Who knew how many different types of steel there are? Some harden in oil, some in water, some even in air. It was quite a learning experience. I would never have guessed that the dew point inside the furnaces was an important factor in the successful hardening of steel, but it was one of many things we had to keep track of.

[@Malakawaka]

I'd love to see Steve explain those hardening treatments inna video of this sort. I don't know the technical name in English when you put red hot iron in burnt oil and the outer layer turns into a kind of black anodized steel

[@craigcorson3036]

@@Malakawaka Explanations of the process can be found online. I don't remember specifics, but it has to do with rearranging the crystal structure of the steel, turning it from austenite to martensite.

[@Malakawaka]

@@craigcorson3036 great!

[@craigcorson3036]

@@Malakawaka You may find this informative: kzbin.info/www/bejne/rqavY6yKYqdliq8

[@callumhunt1348]

This is a big question. From the basics, assume atoms are balls (bearings), balls can stack on top of each other, think of it as layers of whats shown in the video. If the layers lying on top of each other follow a regular repeating pattern, they are called Crystalline, or crystals. However, atoms might not always arrange in the same fashion. The differences between these are called crystal structures, where the distance between neighbouring atoms can change. So a single metal can have different crystal structures, these can then be named “phases” of the metal. Alloying elements can also affect crystal structure, imagine trying to squeeze a carbon atom between 10 Iron atoms, it will distort the distance between the iron atoms. So far, metals can have different phases based on a repeating crystal structure which alloying elements can affect. Next, stability. The carbon atoms will have a position within the Iron matrix where they are most stable. But when you heat material, expansion occurs, magnetism changes and phases can also change. All these things allow for the stable positins of allyoing atoms to change, suddenly new positions are occupied and considered stable. Cooling, if you allow the hot alloy to slowly cool, it will return by to the same original phase. If you let the sample heat up to allow grain growth as Steve described, this is annealing. Normally generates softer and more ductile materials. If you cool rapidly, there is insufficient time to allow the alloying atoms to redistribute back to their stable positions, and they become trapped! This trapping forces the microstructure into what is called meta-stable phase. This phase, if given sufficient heat and time, will revert to a stable phase. For simple Iron Carbon steels, this how Martensite, the super hard but very brittle phase is formed. This trapping of atoms in metastable positins strains the metal matrix, the binds between atoms, in such a way that restricts dislocation glide, which prevents plastic deformation. So, metals have phases, phases change at temperature, cooling slowly allows a return to original phase, cooling rapidly allows a formation of a different phase, often thought to be harder Theres a lot more to talk about here….. a lot But thats the idea, if you cool at different rates you can generate different crustal structures which the material properties are highly dependent upon

[@kauemoura]

Today I learned that, by adding heat to a metal, you increase its grain size, thus making it more ductile.

[@texasslingleadsomtingwong8751]

Sort of . If heat is slowly reduced then ductility is maintained . But. If temperature is rapidly removed then grains form and solidify rapidly causing hardness (mohs) and brittle characteristics . This is where the metal fun goes off in the ditch . Its a balance of desired traits that an engineer or metallurgist are a seeking . It gets really nuts when alloys or base metals are changed from iron ( steel) to tungsten, titanium , and aluminum .

[@NikoMoraKamu]

normally yes but also depends on the alloy , some high cromiun steels become less ductile with high heat and tend to break , steel alloys are amazing with little variations in materials and heat treats the properties can be completly different

[@dannypatrick8671]

worked in heat treat for years and have been a welder for several decades....one 0f the best hands on videos I have ever seen

[@afafsgdchdhdg]

I did my Masters project on material science and I have to say his explanation was out of this world. So much clarity

[@hupekyser]

How on earth are you that good at breaking down, explaining and articulating a complex subject. Wow. That is pure talent.

[@rre9121]

Gosh dang it. I spent all day doing grain size analysis in the lab, I guess 8 more minutes of it won’t kill me.

[@Rapidcouplescounselling]

Degree qualified Materials Engineer here. This is brilliant. Well done explaining something simple that has profound impacts on metallic properties.

[@kazuhideogawa7768]

Wow... when I learned about heat treatment of metals back in may this year, I didn't really understand why bigger crystals led to a more ductile metal. I just learned it as a fact. This video helped me to understand it better. Thank you.

[@matthewdnewton2437]

“Im going to jiggle these balls around” KZbin : demonetised

[@name7692]

1:54

[@robsemicolon]

Steve: Makes a genuinely informative and interesting video KZbin: "lMaO He SaId JiGgLe tHe BaLlS aRoUnD"

[@robsemicolon]

@@Nihilova Joke's on you, I never get invited to parties

[@BarryChumbles]

Best comeback ever :-D

[@ArcheoLumiere]

@@BarryChumbles r/kamikazebywords

[@levis1956]

This video has just intuitively explained about 6 weeks of materials lectures at university in less than 9 minutes. Thanks for making such great videos Steve!

[@thatguy431]

man where were you when i was in materials science?! i remember trying to understand the movement of dislocations and just not being able to visualize it. this model is amazing!!

[@diamondflaw]

Oooh, now I'm wondering if one made with differently sized disks (so they'd fit nicely within the same depth) could be used to show grain structure within alloys.

[@gizmoguyar]

Now that's an awesome thought.

[@dfunited1]

I was thinking how difficult it would be to get correctly spaced plexiglass. Then I reread you comment and you said discs. You could probably do something like that with metal washers. Hmm

[@TheRainHarvester]

Diamondflow , that is a great idea. I did that in a simulation video. "Primordial Particle System - The Trailer". That one shows the metallic structure. But "heart beats and blood flows" shows the different diameters (each color had a different radius and also different velocity). I think you and gizmoguyar might really like these 2 videos.

[@andraslibal]

People working in granular physics do that a lot the problem is you get very large friction between the discs and the plates. A really cool and interesting thing I did once was to work with photoelatsic discs, the beauty is that they allow you to see the force chains inside. www.eurekalert.org/multimedia/pub/115882.php

[@toropazzoide]

I'm dumb. Like really dumb. I put a c instead of a s in disks and was VERY confused for more time that I'd care to admit.

[@HammyTechnoid]

I'm an audio guy from way back when cassettes first came on the scene, and I remember when some manufacturer, maybe AKAI, came up with "Glass Ferrite Heads" and how they were so called "impervious to wear"... You're explanation and demo really gives insight to the metallic structure of those type of heads. I still own machines with "Ferrite" heads, and after more than 30 years, they barely show any wear. Of course, they do wear, but to such a small degree compared to softer "Permalloy" heads, which are more common, and probably cheaper to produce.

[@giuseppezurlo2385]

According to me, this is your best video after the chain fountain one! No surprise it's always based on discrete elements, which makes everything so transparent ... well done!!!

[@AbeGotBored]

Dude. I don’t watch tv, I get all my inputs from KZbin. And I’m super frugal with my subs. Been watching you for a long time, and I love both your models and how you can relate complex ideas in a way anyone can understand. But this video got me. I’m subscribed! Thanks for what you do, and lots of continued success!

[@omarsatar2003]

Thank you Steve! I’ve worked years in metallurgy lab in a foundry and that’s why I really enjoyed this demonstration.

[@StormBurnX]

It makes me so happy to see a pebble steel on your wrist in a video about steel pebbles!

[@tfsupp]

Helps to explain why vibration is used for stress relief in castings and machined items rather than leave out in the weather for years or using low heat cooling cooling cycles they are placed on vibrating tables. Love your channel

[@joshz8803]

Your voice and mannerisms are very pleasing. Fantastic job explaining things.

[@c.james1]

"I'm going to jiggle these balls around" - Steve Mould, 2019

[@ScottNguyenRCAC]

Lmao. I heard he said that me check to see if someone comments on that 😂😂🤦🏻‍♂️

[@doggonemess1]

@@ScottNguyenRCAC Me too. I'm going to make a loop of 1:51 - 1:53.

[@name7692]

1:54

[@doubleirishdutchsandwich4740]

1:40 Atoms and molecules are "jiggling". Trademark Richard Feynman.

[@neilAneerGAmAI]

DoubleIrish DutchSandwich Legendary

[@_TheMushroomMan]

this is the only guy who could enter my reccomendations with a video on a topic that i dont care for, and make me watch it all

[@Jono.]

This is eventually how I came to understand annealing/heat treatment and Austenite phases of steel for my Materials course in college. I think this is an awesome demonstration and review, thanks for putting this together

[@Strothy2]

Gotta say this was way better explained than back in machinist school...

[@derekantrican]

I think Destin from SmarterEveryDay said he was working on a video about this same topic (after seeing Veritasium's video about the shade balls)

[@OscarZoroaster]

yeah..this reminded me of Cody'sLabs video "modeling a gas with magnets"

[@TheRainHarvester]

Derek and paynoattention, I did a few videos on this too. I even varied radius, and speed of different particles in the same simulation. I think you might like these experimental videos. Search "Primordial Particle System - The Trailer", there is another where I got heart beat behaviour!

[@shinigamimiroku3723]

I watch blacksmithing shows, but never really understood why stuff like warping and breaking happened, and this video really helped those events make more sense.

[@yurykomarinskiy9497]

OMG!!! I Wish I had such explanation back in the university days. It finally makes sense why you do cool fast at first, then heat back moderate for a while. Generally speaking you are just tunning grain size. Rough at first approach and then remove garbage micro grains in the second one.

[@Brodysseus113]

Liked for that “WEEE” edit

[@PeterKudelin]

Steve, how do you come up with these smart, original ideas?? What a smart person

[@Vid_Master]

Great video! I already knew about some of the concepts behind this, but showing it visually allowed me to understand it further. Thanks

[@cricket700612]

I worked in Aerospace for two decades and I always envisioned the annealing-oven slow temperature drop was to allow the grains to grow... Softening the (Aluminum Alloy) material. I never looked that closely at steel....or diamonds. Good content!

[@domramsey]

6:34 Ohhhh, that's a nice beaker pour. I do like a good beaker pour.

[@ugluwuglu]

Unusually cool demo. Thank you for making this video!

[@dolphin64575]

This makes my last few years of watching Alec Steel make so much more sense. Thank you Steve!

[@Astrovite]

I think you could imagine the grain as a net. The larger the spacing is in the net, the easier it is to escape, or in this case, bend out of shape. With a smaller spacing being harder to escape/bend out of shape.

[@anonymous4768]

Wow! What a great teacher u r! I was confused for whole of my engg. About this topic kindly make more videos like this. These may be very helpful for engg. Students Great way to arise intrest in engg.

[@drewishaf]

I had to stop and take a breath a 2:00. "I'm going to jiggle these balls around with..." Let me stop you there...

[@alirezzzaei]

That was awesome ! I was really looking for videoes like this to understand the metallurgy concepts. Thank you Steve

[@gyrogearloose1345]

Astounding demonstration of grain boundary and dislocation using the balls with energy input from the vibrator. Thank you very much for that. Good teaching dude . . . keep on!

[@Tensho_C]

i remember watching something about this toy a few weeks ago, it's still really cool

[@theCidisIn]

Weeeee! That's what all metal grains say as they migrate through crystals. Ya know. As ya do.

[@gcewing]

That part made me think of hole conduction in a semiconductor.

[@oldcowbb]

its the dislocation migrating, not grains

[@theCidisIn]

@Mass Debater enough

[@DeniseSkidmore]

Made me think of "game of life" walkers.

[@timeobserver8220]

I loved this video. There isn't enough easy to consume and understand vids on material sciences.

[@PrithwirajBose]

Veritasium would have included 5 formulas explaining this, used some hard-to-understand analogies to explain the same, your way of explanation makes it so easy to understand Physics, Steve.

[@lohphat]

You also said “oriented” instead of “orientated”. Thank you.

[@lohphat]

@Kelven Freitas www.dictionary.com/browse/orient in some UK dialects, an extra syllable is inserted.

[@WetDoggo]

Thank you for this Video, you improved my understanding of matter 👍👍👍

[@noahlankford1]

You have the best way of explaining complex concepts with simple to understand demonstrations. I love it, KZbin best science teacher

[@alexjames1146]

Excellent. Well presented. Focussed on the point. Did not get lost in further explanations. 10/10

[@thediyandpianoguy8665]

This video is brilliant!! I think I understand the process of "Work Hardening" a little better now - such as repeatedly bending a copper wire will increasingly become more difficult, until it eventually snaps. I may have gotten this wrong but from what you've explained I'm guessing that the dislocations within copper grains disperse bit by bit to the grain boundaries until the copper breaks. I could also he totally wrong 😅

[@sofalessskid3354]

Great video as usual Steve! I always feel like I learn something from each of your videos! A very big thank you from Italy!

[@TheRainHarvester]

Skid, "Primordial Particle System - The Trailer", is a similar video you may really enjoy. I vary different attributes of the particles.

[@sieben5163]

gosh i love a good jiggling balls video

[@ExtantFrodo2]

You say that you can't demonstrate anything but annealing in this video but you actually did right at the start when you rapidly rotated the sheet to vertical. This is what happens when quenching heated metal. Smaller grains are "locked in". But what you demonstrated with the vibrations is more akin to tempering (increasing the grain size of your quenched metal). You could actually demonstrate annealing by vibrating while slowly changing the angle of the sheet to vertical while also lowering the volume of the vibrations. All in all this was an excellent primer for anyone wanting to get the gist of grain size and grain boundary effects.

[@JustinDrentlaw]

6:34 Steve knows what his true fans want 👍

[@SteveMould]

That one was for you!

[@JustinDrentlaw]

Aww, thanks man 😁

[@peetsnort]

What I found fascinating is glass used by zeiss is heated up and very slowly over a WEEK to slowly cool down so as not to cause stress lines that would impair the ability of light to move in a straight way through the glass of lenses making it a faster lens... IE the FStop of the lens. The lower the f stop the better the light transmission How clever is man!!

[@nordithen]

That's interesting! However, I think there's a slight correction to be made. The "speed" or f/ratio of a lens is the ratio of the lens' focal length to the diameter of the aperture. The heat treating you described must improve the transmittivity and general optical quality of the lens, but would not make it a faster lens, i.e. give it a wider aperture.

[@giovannipelissero1886]

Incredibile video, very informative! I've already passed the metallurgy exam but this is just perfect. Always great content from you!

[@blakewilliams1478]

Really appreciate the explanation of dislocations, plastic deformation is something I didn't have a good intuition for at the micro level.

[@lukel.5815]

1:48 but without context

[@stevenpaige2005]

Aside from my jiggle joke. That was a great explanation and visual New sub 👍👍

[@ductator4479]

Ngl, you’ve easily become my favourite channel, everything is just so interesting

[@tempus_fugit7366]

Fascinating demonstration. I learned that in jet engines, the individual compressor blades are made from a single crystal nickel alloy, commonly known as a Super alloy. The entire blade piece is forged and machined from a solid billet of this Nickel super alloy. The reason is, those smaller crystal boundaries Steve demonstrated become weaknesses under the extreme heating conditions experienced inside a jet engine. Metal with crystal boundaries as in the video, are subject to creep under high temperature which can lead to shortened life and frequent replacement. while A solid crystal has no boundaries and can be repeatedly heated to near melting temperature without failure.

[@AverytheCubanAmerican]

Thank you Steve, very cool. My favorite guest on Geoff Marshall

[@dickjohnson4447]

Although he looks different in this one

[@billbaggins]

Love the channel Steve, nice to see science without so much shouting 😁 A good simple analogy for a vastly complex subject, I'm an occasional knifemaker so I get to play with heat treatment a bit. Fascinating stuff and so many variables, Be good to see you go further down this rabbit hole. Cheers from Tasmania 🍺

[@TheRainHarvester]

Bill, I went down the rabbit hole! Search "Primordial Particle System - The Trailer", there is another where I got heart beat behaviour! I varied many parameters like you wanted!

[@billbaggins]

🤣 I only went far enuf to get a working knowlegde for the steels that i use. Too much info is bad for a leaky brain 😁

[@vicentev.3517]

Men you are an incredible teacher! Thank you for grinding this concepts into digestible bits!

[@Strumtreppen]

I love the way you do your video as well as the topics. Great job!

[@narayana8249]

My mother was very concerned when she heard: “I’m going to jiggle these balls with a vibration generator”

[@gustre]

2:37 reminds me of conways game of life!

[@charlesballiet7074]

as a blacksmith I thank you for showing such an intuitive model of how the grain structure changes

[@kennyhagan5781]

I remember those. They were downright hypnotic in the right lighting.

[@fatemehshahmohammad8191]

this was more usefull than my four years of studying metallurgy in college

[@bboyjunyor]

Let's just say I feel like Steve's vids are a lot more interesting than the fun-oriented ones you see with other youtube creators!

[@Prof.Polymath]

This is why turbine blades are now formed with a single crystalline structure. Well explained, the magnets visualise things much better than the bubbles on water trick.

[@sudhanshusuryawanshi4699]

I am a Metallurgical Engineering graduate and this was so brilliantly explained that it made me cry. :')

[@aaronmarkstaller]

Do the dislocations affect the density? If you had giant crystals and bent all the dislocations to the edges would it become more dense?

[@Doug_in_NC]

Aaron Markstaller Yes, but only very, very slightly. .

[@kaibrown7214]

"Im going to jiggle these balls" "and to jiggle these balls I'm going to use a vibration generator"

[@marknorman4389]

I studied HNC materials science and didn't really get to grips with this whole principle. nearly 9 minutes of watching this and 💡...Great explanation!

[@gregmead2967]

As a geologist, this is fascinating to me and applicable in a number of ways. First, one thing that we find in igneous rocks is that faster cooling rates for magma give smaller crystal sizes. This is why volcanic rocks typically have crystals that are too small to be seen with the naked eye, whereas plutonic rocks (from magma that cools underground) typically have significantly larger crystals that CAN be seen with the naked eye. Granite is a good example of this. Second, when we look at rock deformation, we find that at shallow depths in the earth, we typically get elastic and brittle deformation (i.e. faults and earthquakes), while deeper in the earth we typically see ductile deformation (i.e. folds). Both of these phenomena are nicely illustrated and easier to understand with your ball-bearing model, and I'm thinking that I may need to make something like this for my classes when I teach about those topics. So many thanks. I may make your video required viewing in my classes.

[@scragar]

Could the replica of the toy also explain how bending a material back and forth makes it snap easily?

[@trapper1211]

By bending it repeatedly you create more and more of these imperfections, so the internal stresses get higher and higher, and eventually they're stronger than forces that keep it together and it brakes

[@mailleweaver]

@@trapper1211 By his explanation, it's not creating imperfections; bending the metal works those imperfections out of the grains and into the grain boundaries. This leaves you with more stable (harder) grains and greater separation between them (since you've moved the voids into the boundaries), so any flex has to come from moving the grains in relation to each other instead of changing their shape. That's a recipe for brittleness. Think of a sand castle: it takes more force to deform a grain than it takes to separate the grains from each other. Once you start trying to bend any part of the castle it'll shatter because the grains separate instead of deforming and you get catastrophic failure.

[@ayhamsaffar8407]

@@mailleweaver i really like your explanation! I was just wondering if the voids created by dislocations migrating to grain bounderies could be used to strengthen the metal? Like if after plastic deformation u heated the metal just enough for the grains to move and spin freely they would eventually settle in a position where the grain bounderies fit into each other like lego blocks. This would mean u would have to break regular lattice interactomic bonds to get grains to slip around each other and seperate.

[@MidnightMarrow]

@@ayhamsaffar8407 I mean if you bent the metal and heat treated it, you would strengthen it in that particular shape. I don't think it would do what you asked though.

[@dickJohnsonpeter]

it's being work hardened and the metal becomes harder and more brittle, maybe for the reasons explained above.